Resolution vs. Screen Size on Phones
Updated: September 09,2022
When looking for a new phone, its screen size will most likely be an important factor to consider. There’s a tradeoff between resolution vs. screen size on phones. Some folks prefer pocket-sized smartphones, while others would rather have a large display, so they can easily look at YouTube or Netflix videos on their mobile devices.
In reviews, you’ll often see the smartphone’s screen described with both size and resolution. In general, more affordable phones tend to have lower resolution compared to the more premium ones, but, as a rule, the larger the screen real estate, the higher the resolution. To better understand what we mean, let’s look at what display size, resolution, and pixels are.
Display Size
The size of the screen is often expressed either in inches (in) or centimeters (cm). That dimension always refers to the phone’s diagonal length. Like with TVs, it will give you a general idea of how large is the display on the phone, but the sizes aren’t as standardized as for TV screens. Screen sizes can go up to 8-inches for the latest foldable phones, and we’ve already seen Android phones with tiny 3-inch screens.
The quality of the screen depends on several other factors, such as its refresh rate, resolution, or type. Therefore, the size of the screen is not as crucial for the image quality on your display as you may think.
Screen Resolution
The term “screen resolution” refers to the number of pixels that make up your display. This value is represented as width by height. A phone’s pixel size is directly related to the size of the screen in relation to its resolution (the larger the screen, the more pixels you’ll have to fit into it, or the bigger the individual pixels will be if you stay at the same resolution).
You are likely familiar with terms like HD, Full HD, Quad HD, or 4K. These directly represent resolution values of video recordings, and for a screen to reproduce them faithfully, it needs to have the same or higher native resolution. Comparing the video quality of an HD and a 4K recording makes it very clear how having a screen with a higher resolution is essential for watching videos or playing video games. Therefore, phone screen resolution will be an important factor when you are looking for a new phone to watch your favorite TV shows on.
How does HD resolution compare with 4K? For example, HD or high definition is 1280 x 720 pixels (px) while 4K (ultra high definition) is 3840 x 2160 px for screens with classic 16:9 widescreen aspect ratios. These values represent how many pixels are in a single row and column of a screen.
Pixels
Pixel (short for picture element) is the smallest dot that forms the image on your screen. Each pixel has red, green, and blue elements referred to as subpixels, and they look similar to the picture below.
Most Common Screen Sizes
As a reference, here are some of the most common widescreen resolutions that you will see used for video recordings, TV, and computer screens.
| Resolution | Horizontal Pixels | Vertical Pixels | Total Pixels |
| SD (480p) | 720 | 480 | 345,600 |
| HD (720p) | 1,280 | 720 | 921,600 |
| Full HD (1080p) | 1,920 | 1,080 | 2,073,600 |
| Quad HD (2K) | 2,560 | 1440 | 3,686,400 |
| Ultra HD(2160p) | 3,840 | 2,160 | 8,294,400 |
| 8K (4320p) | 7,680 | 4,320 | 33,177,600 |
Note that companies use 4k and Ultra HD interchangeably, but really, consumer TVs and monitors are at Ultra HD (2160p) resolution with 3,840 horizontal pixels, yet real 4k is actually 4,096 by 2,160 pixels. This resolution is used in digital cinema and professional production videos rather than commercial TV sets, smartphones, and monitors, though.
PPI (Pixels Per Inch)
You should note that when comparing the resolution vs. screen size on phones, you don’t always get the exact number of pixels per inch. Pixel density or PPI represents the concentration of pixels on one inch of screen real estate. The higher this value is, the sharper and better-looking the display will be. For example, if you have the same resolution on a 6.5-inch phone and one with a smaller 5.5-inch screen, the image would look clearer and more detailed on a smaller screen.
You’ll often see this value next to your phone's resolution and screen size. If it isn’t shown, here’s how you can calculate it with the mobile’s screen size and resolution.
You need to use the Pythagorean Theorem to determine how many pixels are in a diagonal.
diagonal in pixels=width2+height2
Then you have to divide the length of the diagonal in pixels with the length in inches.
PPI=diagonal in pixelsdiagonal in inches
In our example, we will calculate the PPI of a phone with 1,080 by 2,400 pixels and a 6.7-inch screen resolution.
diagonal in pixels=1,0802+2,4002
diagonal in pixels=1,166,400+5,760,000
diagonal in pixels=6,926,400
diagonal in pixels=2,631.805
Now that we know the diagonal phone resolution, it’s easy to get PPI.
PPI=2,631.8056.7=393
How is this relevant for the next smartphone phone you are planning to buy for your kid or treat yourself with? It’s generally accepted that 300 PPI is a measure where you won’t be able to notice individual pixels on your mobile screen, and you’ll start having a realistic-looking display. Anything above 300 PPI is fantastic, but some high-end phones come with overkill specs of over 500.
Designing Mobile Applications
Mobile app developers have to consider many different screen sizes and resolutions when working on their software. Due to the physical limitations of the devices, developers have to approach the app building process to finish with a visually appropriate for every iOS or Android smartphone. For phones, screen size is just one of the factors to consider, along with user behavior, preference for portrait or landscape mode, the quality of the touchscreen UI, etc.
Types of Mobile Displays
There are many different screen types in use nowadays, like AMOLED, LCD, LED, TFT, IPS, PLS, LTPO, LTPS, and others. Furthermore, these technologies are in constant development, and we get different smartphone screens like Super AMOLED Plus or Super Retina XDR. These technologies have different pros and cons.
For example, LCD screens perform better in outdoor conditions and have a more natural color reproduction. In contrast, OLED screens offer more vivid-looking images and better viewing angles.
Final Thoughts
In our resolution vs. screen size guide, we’ve analyzed how these values interact and how to interpret them if you are in the market for a new smartphone. If you are looking for a smartphone primarily to listen to music, make calls, and send messages, save some money with a budget screen option.
If you are an aspiring or amateur photographer, you should opt for a smartphone with a larger display and a higher display resolution. It goes without saying that this is secondary to camera quality, but it will help you see the results more accurately without having to work on an external device. We at KommandoTech prefer devices with hi-res screens as they are more versatile for everyday use.
Frequently Asked Questions
FAQ
Phone resolution and sizes that phones come in aren’t the same. The screen can be larger and still have a lower internal resolution, resulting in a pixelated image, where you can discern each dot that makes up the image. Conversely, a smaller display with a higher resolution will result in a clearer and more natural-looking picture. Each screen has a certain number of pixels per inch (PPI), and this should be your indicator of how clear the picture will look on it. Screens with more than 300 PPI are considered optimal for use on smartphones.
Screen size and resolution are significant factors as we spend most of our time looking at our phone displays. Both factors directly contribute to image quality, and you should always have them in mind when choosing a new phone. That said, resolution directly affects the clarity of the picture, but you’ll have to decide for yourself just how much you need by testing out multiple devices.
Having at least 300 PPI is considered optimal for viewing images, video content, and browsing. How many pixels that ends up being (and hence, what resolution you’ll need) will depend on the size of the screen. You’ll achieve 300 PPI much easier on smaller screens, so the internal resolution can be lower as well.
Size and resolution are two different aspects of a screen that are nevertheless closely related. Our Resolution vs. Screen Size on Phones guide above covers how these factors are related and what to look for when buying a new smartphone.
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With a degree in humanities and a knack for the history of tech, Jovan was always interested in how technology shapes both us as human beings and our social landscapes. When he isn't binging on news and trying to predict the latest tech fads, you may find him trapped within the covers of a generic 80s cyberpunk thriller.
